Field of the Disclosure
The present application relates to a liquid crystal display device, and more particularly, to a fringe field switching mode liquid crystal display device.
Description of the Related Art
In general, an LCD device displays images by controlling light transmittance of liquid crystal with dielectric anisotropy using an electric field. Such an LCD device includes a color filter array substrate and a thin film transistor array substrate combined with having a liquid crystal layer therebetween. The color filter array substrate is provided with a color filter array, and the thin film transistor array substrate is provided with a thin film transistor array.
In order to improve a narrow viewing angle of the LCD device, a variety of new modes applicable to the LCD device are being researched and developed. In accordance therewith, LCD devices being driven in one of an in-plane switching (IPS) mode, an optically compensated birefringence (OCB) mode, a fringe field switching (FFS) mode and so on, are being used as wide viewing angle LCD devices.
Among the wide viewing angle LCD devices, the IPS mode LCD device enables a lateral electric field to be generated between a pixel electrode and a common electrode which are arranged on the same substrate. As such, major axes of liquid crystal molecules are aligned along a lateral direction parallel to the substrate. In accordance therewith, the IPS mode LCD device can provide a wider viewing angle compared to a twisted nematic (TN) mode LCD device of the related art.
Such an LCD device includes an LCD panel, a gate driver, a data driver and so on. The LCD panel includes a plurality of pixels arranged in a matrix shape. The gate driver is used to drive gate lines on the LCD panel. The data driver is used to drive data lines on the LCD panel.
Also, the FFS mode LCD device has been derived from the IPS mode LCD device. The FFS mode LCD device allows a pixel electrode and a common electrode to be formed from a transparent conductive material. As such, the FFS mode LCD device can optimize transmittance of a pixel region.
FIG. 1A is a planar view showing a pixel structure of an FFS mode LCD device according to the related art. FIG. 1B is a planar view showing a pixel structure of the related art which further includes a white sub-pixel and secures transmittance.
Referring to FIG. 1A, an LCD panel of the FFS mode LCD device according to the related art allows a single pixel to be configured with a red (R) sub-pixel SP (hereinafter, “red sub-pixel RSP”), a green (G) sub-pixel SP (hereinafter, “green sub-pixel GSP”) and a blue (B) sub-pixel SP (hereinafter, “blue sub-pixel BSP). A thin film transistor TFT which used as a switching element is disposed in each of the sub-pixels SP.
Such an LCD panel adjusts light transmittances of the red, green and blue sub-pixels RSP, GSP and BSP, which are included in the single pixel P, by apply data signals to the red, green and blue sub-pixels RSP, GSP and BSP. In accordance therewith, the single pixel can display (or realize) a desired color.
Meanwhile, a recently required high definition LCD panel with the pixel structure of FIG. 1A cannot secure a sufficient transmittance. To this address this matter, it is proposed another pixel structure which further includes a white (W) sub-pixel SP (hereinafter, “white sub-pixel WSP”) as shown in FIG. 1B.
Actually, an FFS mode LCD device allows a single pixel to be configured with white, red, green and blue sub-pixels WSP, RSP, GSP and BSP as shown in FIG. 1B. The light transmittances of the sub-pixels SP are adjusted on the basis of data signals applied to the sub-pixels SP. As such, the FFS mode LCD device can display a full color image.
In this case, the white sub-pixel WSP is used to secure transmittance rather than enhance color reproduction properties. As such, the single pixel can secure sufficient brightness.
However, the related art LCD panel with the pixel structure of FIG. 1B must reduce areas of the red, green and blue sub-pixels RSP, GSP and BSP because of further including the white sub-pixel WSP. Due to this, it is difficult to reproduce desired colors.
In other words, the pixel P further including the white sub-pixel WSP can secure a sufficient transmittance, but must deteriorate color reproduction properties due to the area-reduced of each sub-pixel SP.